The present inventive concept relates to a pulsed laser system.
Since a laser was invented in 1960s, researches have started extensively on industrial applications of the laser from 1970s. Since 1980, the laser, especially CO2 laser, has been utilized to various fields such as industry, medical care, communication, display, and the like.
Also, a solid state laser appeared in 1980s due to development of a diode laser. Because the solid state laser can be applicable to fields to which a conventional gaseous laser cannot be applied, demand for the laser has been increased. Thus, laser application fields are becoming extremely broad, for example, an industry field such as laser working, laser cutting, laser welding, laser punching, laser trimming, laser etching, a medical field such as dental treatment, spot removal, tattoo removal, hair removal, LASIK operation, an academic field studying on interaction between laser and material, a national defense field, and a cultural field.
Development of industrial technology requires high precision and productivity in the field where the laser is used. In order to meet the requirements, an ultrashort laser beam has recently been utilized in various fields. The ultrashort laser beam is generally called a femtosecond or picosecond laser beam.
The ultrashort laser beam has characteristics that an optical energy is focused for a very short time (e.g., about 10−12 to 10−15 seconds) to emit light. Thus, the ultrashort laser beam exhibits different characteristics from those of a conventional laser beam. For example, when a medium is provided with the ultrashort laser beam, the ultrashort laser beam is irradiated for a shorter time than for a time for which heat is transferred to the medium such that it may be possible to avoid thermal effect or thermal deformation occurred in a conventional laser process. Since the ultrashort laser beam can process a medium without damages to a surface of the medium, it has been used in fields wherein precise and fine treatments are required (e.g. semiconductor, electronic chips, medical care, etc.).